In his poetry, Muhammad Ibn al-Dheeb al-Ajami praised the Arab Spring revolts that have toppled dictators in four Arab countries since early last year and criticised Qatari Emir Sheikh Hamad bin Khalifa al-Thani.
Mr Ajami, 36, who was not present in court, has been jailed in solitary confinement for almost a year during which he has not seen his family, according to his lawyer Nagib al-Naimi.
“This is a tremendous miscarriage of justice,” Mr Naimi told Reuters after the verdict, adding that he would appeal.
Mr Ajami faced charges of “inciting the overthrow of the ruling regime”, which carries the death penalty. Qatar’s penal code provides sentences of five years in prison for criticising the country’s ruler.
Qatar, a close ally of the United States and major oil and gas producer in the Gulf with a large American military base, has escaped the unrest engulfing other parts of the Arab world.
Doha finances and hosts the pan-Arab satellite TV network al-Jazeera, which has assiduously covered the Arab revolts, though it gave scant coverage to an uprising last year in neighbouring Bahrain – ruled by a related Gulf Arab monarchy.
The Qatari government has backed the armed revolt in Syria, a successful NATO-backed armed uprising in Libya, and street protests that ousted rulers in Egypt, Tunisia and Yemen.
But freedom of expression is tightly controlled in the small Gulf state, with self-censorship prevalent among national newspapers and other media outlets. Qatar has no organised political opposition.
In October, Human Rights Watch criticised what it said was a double standard on freedom of expression in Qatar and urged the emir not to approve a draft media law penalising criticism of the Gulf emirate and its neighbours.